#include <bits/stdc++.h>
using namespace std;

using i32 = int;
using i64 = long long;
#define int i64

signed main() {
    int n;
    cin >> n;
    string s;
    cin >> s;

    vector<int> neg(n);
    vector<int> zeros(n);
    vector<int> pos(n);

    neg[0] = s[0] == '-';
    for (int i = 1; i < n; i++) {
        neg[i] = neg[i - 1] + (s[i] == '-');
    }
    zeros[0] = max((int)(s[0] == '0'), neg[0]);

    for (int i = 1; i < n; i++) {
        int zer = s[i] == '0' ? 1 : 0;
        zeros[i] = max(neg[i - 1] + zer, zeros[i - 1]);
    }

    pos[0] = (s[0] == '+');
    for (int i = 1; i < n; i++) {
        int opt = s[i] == '+' ? 1 : 0;
        pos[i] = max({pos[i - 1] + opt, zeros[i - 1] + opt, neg[i - 1] + opt});

    }

    cout << pos[n - 1] << endl;
}